Glossary
Glossary-8
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Reference potential
Potential from the point of view of which the voltages of the involved circuits are
analyzed and measured.
Repeat accuracy
The repeat accuracy identifies the maximum deviation among the measured/out-
put values that then occurs, when the same input signal is again applied or the
same input value specified. The repeat accuracy relates to the rated range of the
module and applies to the settled temperature state.
Repeater
Equipment for the amplification of bus signals and connection of →bus seg-
ments over long distances.
Resolution
With analog modules, the number of bits which represent the digitized analog
value in binary. Resolution depends on the module and with analog input mod-
ules on the →integration time. The precision of the resolution of a measured
value increases with the length of the integration time. The resolution can be as
many as 16 bits, including sign.
Retentivity
Data areas in data blocks, and also timers, counters and memory markers are
retentive when their contents are not lost upon a complete restart or POWER
DOWN.
Scan time
The scan time is the time required by the → CPU to scan the → user program
once.
Segment
→ Bus segment
SFC
→ System function
Signal module
Signal modules (SM) form the interface between the process and the program-
mable logic controller. There are input modules, output modules, input/output
modules (both digital and analog).